Why can't you bring fresh fruit across the border?

Fruit can be carried across many international borders, including the US/Canada and between most countries in Europe.

However, many other countries, including Australia do not permit many food products from being imported by passengers, including meat, diary, fruit/vegetables and plant seeds because of the risk of the accidental import of bugs and diseases that would effect local produce.

You would need to check with the border agency responsible for the country you are visiting to see what is prohibited before travel. Any prohibited items will be seized and destroyed and fines may also be levied. The Australian border agency, for example, impose on-the spot fines of $220. A false declaration on the customs form would lead to a fine of up to $60,000 and 10-years in jail.